Oscilloscopes include large numbers of functions which in themselves have an increasing number of parameters to be controlled. These oscilloscopes require the operators to become increasingly intimate with those functions through the operational controls. The half dozen controls such as X, Y and Z axis of early oscilloscopes has increased to forty to fifty with the present day oscilloscopes. It is therefor likely that future oscilloscopes will require another order of magnitude of control parameters. However, as the number of controls increases, the instrument appears increasingly complex to the user which decreases its effectiveness. Although the users tolerance for complexity has increased with the availability of complex instruments, it saturates at a level which is dependent on his motivation, which is in turn dependent on the complexity of the problem to be solved and his need to solve it. Therefore, the complexity of many instruments, including oscilloscopes, have now approached or surpassed the saturation level of the tolerance of most users. It is necessary to develop methods to reduce this perceived complexity to below that threshold.
The typical solution to complex instruments involves the use of a control panel with a multiplicity of fixed functions where each function has a single control. However, as the number of controls becomes large, it is not possible to observe the state of the instrument by observing the control setting, inasmuch as it is difficult to find the control itself. Similarly, adjustment is difficult since it is necessary to both find and adjust a particular control from a field of controls. Also, as the complexity or flexibility of the oscilloscope increases further, such as for additional channels, the number of controls is multiplied, making adjustment and interpretation of the oscilloscope display increasingly difficult.
One solution to this problem is to bypass the problem by trading off flexibility for operational simplicity, such as by restricting the flexibility of the instrument. A second trade-off could be made by restricting the user rather than the application. In this manner, the complex instruments could only be made available to people having complex operating systems, such as mini or microcomputer systems. The user of this system must then be a technician or programmer familiar with the function of each of the instruments, the computers and their communication protocols. A disadvantage of this approach is that the important parameters become embedded within the controlling system and are accessible only by tedious system inspections. Furthermore, system checkout becomes difficult when intermediate results cannot be examined, and the system is awkward and expensive.
Another technique which has been used in some logic analyzers and automatic test equipment is the use of a directed sequence of menus. The menu often requires the dedicated use of the old display device during the set-up or initialization process. In these applications, the system set-up is normally complex enough to require prompting by the instrument, and is done only once for large number of measurements. Control settings are not seen while viewing measurement results. However, for an analyzing instrument, the menu technique is undesirable since the controls are not interactive by the user while viewing the system measurement results. For example, the vertical gain of an oscilloscope is usually adjusted to get the waveform to fill a particular portion of the screen rather than to set the gain to a particular vertical scale factor in volts per centimeter which would allow direct user signal interpretation without reviewing the selected menu scale value. It is therefore necessary to devise an instrument which will reduce the complexity to the user while not reducing its convenience, flexibility or capability.